multiphonics

…of new techniques, such as multiphonics, in which two or more pitches are sounded simultaneously on a single woodwind instrument.

…he learned the technique of multiphonics, by which a reed player can produce multiple tones simultaneously by using a relaxed embouchure (i.e., position of the lips, tongue, and teeth), varied pressure, and special fingerings. In the late 1950s, Coltrane used multiphonics for simple harmony effects (as on his 1959 recording…